You never know when it’s going to happen. A flying saucer pulled off the side of the highway with the hood up, alien waving a tentacle wielding what could be a sparkplug, a cellphone or a ray gun and shouting, “Znelflgjpd knorb zlothkpmzus!” How would you respond? You’ve hit the alien language barrier. With NASA’s Kepler telescope spotting potentially habitable planets by the dozen outside our solar system, it may be time for us to start brushing up on our extraterrestrial language skills, or get ready to tutor E.T. in Earthish as a Second Language.

Most of us are familiar with the Search for Extraterrestrial Intelligence, an effort by many people all over the world to find evidence that there’s someone else out there. The SETI Institute is a non-profit organization started a quarter century ago to scan the heavens with powerful radio telescopes. Traditional SETI is the equivalent of waiting by the phone for the cool kids in the galaxy to call and invite us to come out and play. “Active SETI,” also called CETI (Communication with Extraterrestrial Intelligence) or METI (Messaging to Extraterrestrial Intelligence), is our attempt to make the first move, but the results so far have been a lot like the response to a desperate online dating profile — an Eerie Silence.

With projects like “Message from Earth” or “Hello from Earth,” which have collected text messages by the hundreds to launch at the dartboard of space like an anthology of men’s-room graffiti, it’s true that we may not be making the best first impression. There’s a fair argument that we should stop announcing our presence to potentially hostile aliens no matter what we’re telling them. But before we can worry about any of that, there are two big questions to answer: Is anyone even listening to us, and if so, will they be able to receive and interpret our messages?

The Great Extraterrestrial Debate

Earlier this year, the Centre For Inquiry hosted a symposium in Toronto called “The Great Extraterrestrial Debate” in which three distinguished panellists discussed why anyone should believe that extraterrestrial life exists. Dr. Ray “Ray Jay” Jayawardhana, astrophysicist and author of Strange New Worlds: The Search for Alien Planets and Life Beyond Our Solar System, discussed the search for habitable planets; science-fiction novelist Robert J. Sawyer played devil’s advocate and observed we have “zero evidence” that there is so much as “pond scum” anywhere other than on Earth; and Dr. Seth Shostak, Senior Astronomer at the SETI Institute in Mountain View, California, gave his views on what we can expect to find in the not too distant future.

Dr. Shostak bet everyone in the auditorium a cup of Tim Horton’s coffee (Canadianizing his usual Starbucks wager) that we will get an ETI signal “in the next two dozen years or so” (and he’s not the only expert who thinks so). But when we stumble upon that signal, he cautioned, “don’t expect that what’s on the other side of that microphone is a little soft squishy grey guy with big eyeballs and no sense of humour. It’s going to be a machine.”

After the presentation, Dr. Shostak agreed to an interview and proceeded to rain on this journalist’s parade by pronouncing that when we finally intercept a message from an extraterrestrial intelligence, it is most likely that (1) the message will have been relayed by an artificial intelligence, (2) the civilization of the originating ETI will have been extinct for eons, and (3) the message will be undecipherable because it will have been intended — and encoded — for someone else. And he says even if we do decode the message it will be “like the way Julius Caesar talks to us. It’s one way.” Shostak asserted, with no candy coating, that conversations with ETI are unlikely to happen. When we detect something, we will only be eavesdropping uncomprehendingly on a recording that is not even directed to us — maybe something like the extraterrestrial equivalent of a Doritos commercial (like the one broadcast into deep space in 2008).

Even if alien beings do start talking to us and have something to say other than “Ack ack, ack ACK ACK!” (or in Earthish, “Hasta la vista, baby!”), the language of an ETI will surely differ from human languages in unimaginable ways. But, assuming we share a certain degree of sensory compatibility with ETI (auditory or visual communication being most useful from our perspective), it’s conceivable that we could learn their language.

Alien Language Barrier

There are three barriers to interstellar communication with an extraterrestrial intelligence:

• finding each other,
• crossing the distance (or rather the waiting for a message to cross that distance), and
• establishing common terms of reference.

The first two are tricky. Given the expense of interstellar travel, and the galactic economy being what it is these days, our first communication with an extraterrestrial intelligence will surely happen at a distance. We’d be lucky if ETI were to crash-land on Mars. Still too far to visit, but near enough that we could have a chat, just not face-to-face. Pity, because that rules out a whole bunch of communicative shortcuts. Pointing to a mountain, for example, or drawing it or suggesting the concept through gesticulation, is easier than describing it in some more abstract way like vocalizing or writing. But language is more than communication. Language exists precisely for saying what you can’t express by pointing or snarling or what have you. So by locating our new friends on Mars we can concentrate on the linguistic aspect of communicating with ETI.

When considering “common terms of reference,” we may know nothing about ETI now, but we should be able to deduce some things about an ETI who’d be in contact with us. ETI is by definition intelligent (whatever we choose to mean by that). ETI must comprehend math, physics, chemistry, astronomy and binary computation, or they wouldn’t have gotten close enough to talk to us. If we’re able to exchange signals, it means ETI is able to use technology compatible with ours for communication. We’ll have more than nothing in common, at any rate. These suppositions might almost be enough to pave the road towards mutual comprehension once we make our initial connection.

Considering our technology and physiological faculties, the most obvious modes for communication with a Mars-stranded ETI are radio or light. Carl Sagan’s Contact covers a lot of ground about the many ways information can be layered in a signal, as do Robert J. Sawyer’s novels Golden Fleece and Factoring Humanity. Information can be coded in a pulse, like Morse Code or, more simply, binary code. For a signal-sender to indicate “Hey, look at me; I am an intelligent being,” the pulse can be used to present highly recognizable patterns like sequences of prime numbers. Such patterns can be grouped in clever ways with the hope that the receiver will be able to figure out how the sender intended the groups to relate to one another. For example, you could send two sets of data and hope the receiver guesses that the sets can be combined to form a grid with an X-axis and a Y-axis. The data arranged on such a grid can display an arranged sequence of, say, black squares and white squares revealing an image (which some Earthlings call a bit map).

Because there are many ways to transmit binary code, several streams of data can be sent simultaneously, with the streams relating to one another and combining to reveal more information. Various characteristics of the signal can be manipulated to encode binary data: modulating between two adjacent radio frequencies, reversing the polarization of the signal from clockwise to counter-clockwise, altering the timing between light flashes in a laser signal, adjusting the intensity of the signal. By all of these means, separately or together, the sender of the message (us or them) can relay data. Two streams of data can be used to convey two dimensions, from which one can construct a 2D image. Three streams could be combined to reveal a static 3D image or a 2D image plus the third dimension of time, a moving image. Four could indicate 2D + time/motion + colours.

So now you’re ready to send and receive all manner of multilayered data-rich signals. But what should we say to the universe? The plaque that Carl Sagan improvised and stuck on Pioneer 10 and 11 with the Adam and Eve sketch by his ex-wife is “information rich” but cryptic to say the least. You, dear reader, know a bit more about Earth and Earthlings than Joe Alpha Centauri does, and how much sense can you make of that plaque? The 1,679-bit Arecibo Message of 1974, which includes a stick figure, looks like digital finger-painting. A stickman doesn’t look much like a man even if you know what both look like. And although the golden oldies record that went up with the Voyager probes was a big improvement, it’s basically a postcard from nowhere saying “Wish you were here” in 55 unknown languages (56 if you include the “whale greetings”). Those are going to be pretty much non-starters for ETI.

Earthish as a Second Language

To communicate at a distance with a being who has the faculty of language but no familiarity with any human language (and no handy Rosetta Stone) requires using a self-explanatory language, a code that can be used to decode itself. Our interstellar language must be interpretable by beings with whom we have no common frame of reference except for inevitable facts (a priori ideas) and universal principles familiar to both parties — those common terms of reference, things like celestial landmarks, laws of physics, chemical elements and mathematics. Pattern recognition is the key to identifying and decoding a message. A sequence of prime numbers is a clear indication of intelligence, because it is the sort of pattern that is unlikely to appear spontaneously. If the receiver of a series of numbers can recognize such a pattern and anticipate what numbers will come next, they can be sure someone is trying to tell them something.

An example of how this “communication from scratch” could work can be found in Sagan’s essay “Quest for Extraterrestrial Intelligence” in which he proposes, “Arithmetical statements can be transmitted, some true and some false, each followed by an appropriate coded word which would transmit the ideas of true and false.” A concept such as 1 + 1 = 2 is easy to convey. Multiple examples of that sort should make the inclusion of 1 + 2 = 5 recognizable as a deliberate mistake.

Shostak thinks mathematics is a very limited way to communicate “the kinds of things that would really interest [an ETI],” matters specific to life on Earth rather than matters of science which they would know without us telling them. But attempts have been made at self-explanatory communicative systems. Lincos (from “Lingua Cosmica”), developed for the purpose of interstellar communication by Hans Freudenthal at the University of Utrecht, was built on the algebraic logic of Alfred North Whitehead and Bertrand Russell. More recently, at the turn of the current century, Dr. Yvan Dutil and Stephane Dumas of Quebec designed a 400,000-bit message, using Lincos as their starting point, which was sent to several outer-space targets in Cosmic Calls I (1999) and II (2003). The transmission began with the Dutil-Dumas message, dubbed the Interstellar Rosetta Stone (IRS), followed by other messages including the Arecibo Message.

The IRS is “something to teach the reader how to read the rest of the communication,” explains Dumas. “The idea is to communicate enough information (via redundancy) so the receiver understands the concepts.” Rather than a stick-figure or “Hello” in dozens of languages, it is a series of symbols which convey increasingly intricate concepts — plus a map of Earth and those Pioneer nudie pictures. It’s just a message in a bottle, but at least it could conceivably be interpreted by ETI. This use of mathematical “cosmic” language in conjunction with detailed images, which in future transmissions could be upgraded to moving images or holograms, could put us well on the way to establishing a shareable language.

We know they’re out there, but they haven’t answered any of our calls yet. No wonder. When you send a message thousands of light years, it ain’t instant messaging. And most of the crap we’ve sent them has been mostly crap. Spammers deserve an empty inbox. But Dutil and Dumas have something to say, and if their message is ever found, it just might start to break down that alien language barrier.

Further reading (PDF):

• Interview with Dr. Yvan Dutil on the use of Lincos in the Dutil-Dumas message
• More details about Cosmic Calls I and II

Evan Andrew Mackay writes about culture and social justice. He is the chair of the Science and Philosophy Book Club for CFI (Centre For Inquiry) Ontario and a regular contributor to Post City Magazine and the Nikkei Voice, the national newspaper of Japanese Canadians. He lives in Toronto.